Moving the trailer set-up is not a problem. I wouldn't tow it set-up but simply moving it across a lot is no big deal. It will get a lot more stress than that during your 1st good windstorm.
Your pic does show new brake assemblies (old brake drums).
The bathroom wall is easily fixed. I just did mine. The factory screws only go into the wood base less than 1/4". I bought new #10 S/S machine screws,
the same length (they are slightly larger than the factory screws). I then counter-sank the screws 1/4" deeper into the slide by drilling holes large enough for the screw head to go in. The fix is very strong and the screws don't penetrate through the base wood piece (which is 5/8" thick). I guess that you could accomplish the same thing by simply buying screws 1/4" longer
. Be sure to drill out the holes in the upper slide part so that the screws don't grip
it but are allowed to pull it down tight against the base wood board.